

//原型的继承，而不是改变构造函数的原型
function User() {}
User.prototype.name = function() {
  console.log("user.name");
};
// let hd = new User();
// hd.name();

function Admin() {}
Admin.prototype = User.prototype;
Admin.prototype.role = function() {
  console.log("admin.role");
};

function Member() {}
Member.prototype = User.prototype;
Member.prototype.role = function() {
  console.log("member.role");
};

let a = new Admin();
a.role();